Wine Chemistry and Biochemistry

3B Biologically Aged Wines 95

Fino Oloroso Amontillado

Balsamic

Floral

Fruity/5

Empyreumatic Spice/5

Fatty/5

Solvent

Balsamic

Floral

Fruity/5

Empyreumatic Spice/5

Fatty/5

Solvent

Balsamic

Floral

Fruity/5

Empyreumatic Spice/5

Fatty/5

Solvent

Fig. 3B.5Odour profiles of fino,amontillado and oloroso wines. For a better visualization the
values of the fatty, fruity and spice series are divided by 5

which has led some authors to seek effective ways of shortening the aging time

without altering the quality of the resulting wines. Some procedures (Ough and

Amerine 1958) involve aerating or agitating the wine in order to accelerate yeast

aerobic metabolism without the need for yeasts to form a film on its surface (i.e.

submerged cultures). The resulting wines have sensory properties that differ from
those typical offinowine and are used for blending with baked sherry. Other proce-

dures use a tray system in order to increase the surface area/volume ratio of the wine

in order to facilitate oxygenation and the development of flor yeasts; this procedure,

however, entails individually processing each tray and produces large amounts of

biomass which impair the quality of the end product. Rankine (1955) proposed

the use of yeasts packed into oak chips in batch production processes. Ough and

Amerine (1972) sought to make the aging process faster by pumping wine to the

top of a tank in order to facilitate aeration and then dropping it on the surface. This

breaks the flor film, which makes this method inadvisable in practice.

Recently, periodic microaeration offinowines was found to shorten substan-

tially their biological aging time (Mu ̃noz et al. 2005). The procedure preserves the

integrity of the flor film. Its effects were examined in a study involving the microaer-

ation of wines aged for variable lengths of time in the presence of two different

yeasts races (namelyS. cerevisiaevar.capensisG1 andS. cerevisiaeF12). The

best results were those for the wines which were previously subjected to biological

aging. Also,S. cerevisiaeG1 proved more effective thanS. cerevisiaeF12 for the

intended purpose.

Aerating wine under biological aging on a monthly basis has been found to

inhibit partially ADH I and ADH II enzyme activity immediately upon aeration.

However, once all oxygen has been used by the yeasts and become a limiting factor

again, ADH II activity rises, possibly as a result of the need to alleviate the excess

of NAD+accumulating by effect of oxidative metabolism and maintain the redox